1. Field of the Invention
The present invention relates generally to a supplemental visual display for a traffic signal and, more particularly, to an apparatus for covering a face of a traffic signal with a warning sign in response to a power failure of the traffic signal.
2. Description of the Prior Art
Supplemental visual display devices for use with a traffic signal and which are activated in response to a power failure of the traffic signal are well known in the art. U.S. Pat. No. 3,863,214, issued to Kerr, Jr., teaches a supplemental visual display for a traffic signal with a stop sign attached to the end of a signal arm. An electromagnet holds the arm in place against the side of the signal light during operation of the light. The interruption of an electrical signal from the controller to the electromagnet will cause the arm to pivot downwardly and away from the signal light.
U.S. Pat. No. 4,642,605, issued to Karp, similarly teaches a power failure warning responsive device having an arm pivotally mounted to the signal light and held in place by an electromagnet. When the power supply to the light is interrupted, the electromagnet releases the arm. An electromagnet releases the arm to pivot downwardly and away from the signal light once electrical flow has been interrupted to the traffic light. A collapsible warning sign unfolds between the arm and the side of the traffic light.
The disadvantage of the above devices is that a driver's first instinct is to always focus on the traffic light when entering an intersection. Therefore, the driver may not have adequate response time when travelling at high speed to realize that the light is inoperative and to then shift his attention to the warning sign which is arranged at the side of the stop light.